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para ‐Quinodimethane‐Bridged Perylene Dimers and Pericondensed Quaterrylenes: The Effect of the Fusion Mode on the Ground States and Physical Properties
Author(s) -
Das Soumyajit,
Lee Sangsu,
Son Minjung,
Zhu Xiaojian,
Zhang Wenhua,
Zheng Bin,
Hu Pan,
Zeng Zebing,
Sun Zhe,
Zeng Wangdong,
Li RunWei,
Huang KuoWei,
Ding Jun,
Kim Dongho,
Wu Jishan
Publication year - 2014
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201402831
Subject(s) - perylene , singlet state , ground state , intramolecular force , antiaromaticity , dimer , excited state , chemistry , aromaticity , photochemistry , triplet state , computational chemistry , molecule , atomic physics , stereochemistry , physics , organic chemistry
Polycyclic hydrocarbon compounds with a singlet biradical ground state show unique physical properties and promising material applications; therefore, it is important to understand the fundamental structure/biradical character/physical properties relationships. In this study, para ‐quinodimethane ( p ‐QDM)‐bridged quinoidal perylene dimers 4 and 5 with different fusion modes and their corresponding aromatic counterparts, the pericondensed quaterrylenes 6 and 7 , were synthesized. Their ground‐state electronic structures and physical properties were studied by using various experiments assisted with DFT calculations. The proaromatic p ‐QDM‐bridged perylene monoimide dimer 4 has a singlet biradical ground state with a small singlet/triplet energy gap (−2.97 kcal mol −1 ), whereas the antiaromatic s ‐indacene‐bridged N ‐annulated perylene dimer 5 exists as a closed‐shell quinoid with an obvious intramolecular charge‐transfer character. Both of these dimers showed shorter singlet excited‐state lifetimes, larger two‐photon‐absorption cross sections, and smaller energy gaps than the corresponding aromatic quaterrylene derivatives 6 and 7 , respectively. Our studies revealed how the fusion mode and aromaticity affect the ground state and, consequently, the photophysical properties and electronic properties of a series of extended polycyclic hydrocarbon compounds.